Glass, brass, granite, tiles and other materials which can be made to have a hard, smooth and impervious surface are widely used as mirrors, windows, walls or displays in both domestic and high-rise commercial buildings. The exterior appearance of premises or buildings is always regarded as a reflection of the image, personality or characteristics of their owners or occupants, regular cleaning of external surfaces are therefore required to maintain a clean, spotless and dust-free look. These surfaces are always shiny, either highly reflective or transparent, good cleaning would therefore require application of a suitable cleansing agent, scrubbing with a soft material such as foam, sponge, wool or cloth, and drying immediately after scrubbing to avoid residual stains.
Many of these surfaces are large and tall and are often found in business districts or shopping arcades where there is a high pedestrian turn-around rate. Conventional cleaning methods using ladder with bucket, mop and wiper become dangerous and inefficient. Furthermore, residual used liquid not completely removed will be collected at the edges and forming mouldy or rusty layer of residue deposit. There is therefore a particular need for an integral unit which combines cleanser application, scrubbing and drying for this kind of surface in one single trait.
DE 4125866 discloses a cleaning device which comprises a rubber blade for wiping and a vacuum suction nozzle for removing residual fluid or particles. This device, however, requires very strong suction power to retain used liquid inside the suction nozzle when the device is lowered and is not satisfactory. Practical experience shows that, unless the nozzle is always maintained in an upward position, dirty residual matter always drips and leaks out of the nozzle, causing inconvenience add nuisance to both the user and passers-by. For domestic users, dripping of dirty liquid on carpeted floors or upholstery can also be irritating.